Coaxial catheters are well-known in the art, being used for applications such as hemodialysis, where separate lumens are necessary to simultaneously remove blood from and return treated blood to a patient. Examples of coaxial catheters for use in hemodialysis treatments can be found in U.S. Pat. No. 5,976,103 to Martin. Such coaxial catheters, generally comprised of one or more inner catheters disposed within an outer catheter, are conventionally connected to extension tubing for the purpose of attachment to a dialysis or other treatment device.
This is generally accomplished by molding a hub over the proximal end of the catheter, which transforms the coaxial configuration of the lumens to a side-by-side configuration so that the extension tubing will lay flat against a patient's skin. The extension tubing is then connected to the hub post-processing via a barbed fitting or the equivalent as shown in U.S. Pat. No. 5,053,004 to Markel et al. The hub overmolding process is typically conducted after first inserting a cylindrical pin into an innermost catheter and C-shaped pins into the other catheter(s). Once the molding process is complete, the pins are removed and separate channels are created for the extension tubing.
There are drawbacks, however, to the above-described standard method. First, use of a post-processing connection system for the extension tubing as opposed to overmolding the hub with the extension tubing in place, provides a much weaker connection and one that can become prone to detachment with higher flow rates. Second, use of C-shape rods in the overmolding process can result in flow disturbances and inefficiencies in a functioning catheter, as well as the formation of bubbles, which causes turbulent flow.
For these and other reasons, it would be advantageous to provide a single bifurcation insert for connection to both the catheter and extension tubing prior to a hub overmolding process to provide a complete product that avoids the common drawbacks associated with the standard manufacturing methods of a multi-lumen catheter with respect to a proximal hub for attachment thereto.